Resistance element.



J A. CAPP.

RESISTANCE ELEMENT.

APPLICATION man APR. 1a. 1916.

1,279,252. Patented Sept. 17,1918.

ALLOY 0F/R0/V, NICKEL, MANGANESE h IDA/6111101:

O n a s @Wi His A om g.

cost of the process, and hence STATES PATENT OFFICE.

Jomt A. canyon COMPANY,

scmmnt'ranr, NEW YORK, assxanon roommmx. Emerald a conroaarron or NEWYORK.

RESISTANCE ELEMENT.

To all whom it may concern.- Be it known that I, JOHN A. Our, a citizenof'the United States, residing at Schenectady, county of Schenectady,State. of.

8 New York, have inventedfcertain new and useful Improvements inResistance Elements, of which the following is a specification.

My invention relates to resistance elements or the like, and moreespecially to resistance elements in which the resistance wire isinclosed in a metallic sheath, with an intervening layer of heatconducting and 7 electric insulating material between the two.

Resistance elements of this character have hitherto been proposed whichare made from an ingot comprising a metal tube of steel other material,a central core of suitable material which for heating 'work and the likeshould have a high specific electric resistance, and a layer of powderedrefractory heat conducting and electric insulating material compactedbetween thecore and the sheath. After the ends of the ingot are stoppedwith washers or swaged or rolled to a size to give to the core wire therequired resistance. The details of manufacture of sheathed wire of thischaracter are fully set forth in a patent issued to Chester N. Moore,August 11, 1914, Serial N 0. 1,107,233, and need not here be morefullydiscussed, except to explain that between each few passes it isnecessary to thoroughly anneal the wire; otherwise the core wire be- Itcomes so hard that further reduction becomes impractical. Many of thebest resistance materials require a considerable amount of annealing,and as this is a rather expensive process, it adds materially to the tothe expense of the finished sheathed wire.

My present invention has for its object the provision of sheathed wireof the general character discussed above, in which the core I wire ismade of a material that is particularly well suited to undergo theoperations necessary for its manufacture without an excessive amount of'annealing and which has at th ejsaine time a high specific resistance,so

0 that the material is particularly applicable to heating and other workwhere'ahigh re sistance is required. I havefound that an alloycontaining, or composed of, iron, nickel, and manganese is particularlwell l suited for this purpose. Alloys 0 iron plugs, the whole is.

Specification of Letters Patent. P t nt t, 17, 1913, Y Application filedApril 1a, 1916. serial m. 92,057,

and nickel have hitherto been used resistance elements,. and manganesehas commonly been present in such alloys in small proportions, forexample one per cent. or less, and in such proportions it has the'effect of hardening the alloys. I have found, however, that when themaganese 1s present in such alloys in substantial proportlons, that itnot only raisesthe resistance of the alloy, butthat it has theunexpected result of increasing their malleability and ductility sothat, because of their malleability, they do not require an exce s siveamountof annealing between the successive passes in the rolling orswaging machine in order to prevent their becoming unduly hard, andbecause of their ductility they may be extended to the required lengthand be kept substantially, uniform in crosssection. At the same time,the manganese imparts to the alloys greatly increased electricresistance, which makes the same particularly suitable for heating andother high resistance Work. I have found the following compositionsatisfactory for the core wire:

Iron 55% Nickel 35% Manganese 10% It will be understood, however, thatwhile I have given the composition that I prefer in practice, that thepercentage of the vari- 'ous constituents may vary and still come withinthe scope of my invention.

Referring, now, to the drawing, the figure shows, partly in longitudinalsection and partly in side elevation, a section of sheathed Wire,embodying my invention and provided with a terminal. The core wire isindicated by the numeral 1, and is formed at the end with an enlargedterminal 2 of the character shown in Whitney Patent #1,095,502;which wasissued April 14, 1914.

The core wire is inclosed by a tubular metalmade is rather readilyoxidized when exposed to the atmosphere at high temperatures, and is,therefore, unsuitable for heating device, and other resistance work 5where the resistance element is run at ared heat and exposed'to theatmosphere' When the material, however, becomes the resistant element ofsheathed wire, this property of rather readily oxidizing is of 10 noconsequence, since the atmosphere is ex- What I claim as new and desireto secure by Letters Patent of the United States, is,- 1 1. A reducedsheathed wire comprising.

a high resistance core wire including in its composition iron, mckel andmanganese, a

. sulating material withm compacted tubular metallic sheath inclos' saidcore 28 wire, and an intervening layer 0 compacted powdered insulatingmaterial within which the resistance element is embedded;

2. A reduced sheathed wire comprising a high resistance core wireincluding in ts 8 0 composition iron and nickel, and manganese inexcessiof one per cent., .a tubular metallic sheath inclo'sin'g saidcore wire, and an in-y tervening layer of compacted powdered inanceelement is embedded. v

3.. A reduced sheathed wire comprisingia resistance core wire composedsubstanh gh .tla 1y of iron fifty-five per cent., nickel thirty-five percent., and manganese ten per 40 cent., a tu ulan metallic sheathinelosing said eorewire, and an intervening -layer of.

gowdered insulating material withm whic the resistance element isembedded.

In witness whereof, I have hereunto set my hand this 17th day of A ril,1916.

JO A. CAPP.

which the resist-ti

